Stents are well known devices for placement in vessels of the human body to obtain and maintain patency of that vessel. The greatest use for stents has been for placement within a stenosis in a coronary artery. When a stent is used for treating a coronary artery stenosis, it has always been necessary to first place a guide wire through the stenosis. The next step in the stenting procedure is typically to pre-dilate the stenosis with a balloon angioplasty catheter that is advanced over that guide wire. The balloon angioplasty catheter is then removed and a stent delivery system that includes the stent is advanced over the guide wire and the stent is then deployed at the site of the dilated stenosis.
Recent improvements in the design of stent delivery systems have made it possible to eliminate the step of pre-dilatation for the treatment of many classes of stenoses. The delivery of a stent to the site of a stenosis without pre-dilatation has been given the name “direct stenting”. However, even with direct stenting, a guide wire is still required as a precursor to advancing the stent delivery system over that guide wire to place the stent at the site of a stenosis. Placing the guide wire requires additional procedure time and additional cost for the procedure.
In U.S. Pat. No. 6,375,660, Fischell et al. describe a stent delivery system with a fixed guide wire that is not steerable. This fixed, not steerable, guide wire system will not be as capable for rapid delivery of the stent through the tortuous coronary arteries as stent delivery systems that are advanced over a steerable guide wire.